The invention relates generally to a vehicle battery monitoring system, and more specifically, to a self-contained measurement device configured to mount to a battery cell within a vehicle.
Hybrid and fully-electric vehicles typically include an array of battery cells configured to power at least one electric motor. Monitoring various parameters of each battery cell may provide data for efficiently operating the array. For example, the temperature of each battery cell, or group of cells, may be monitored to ensure that the cell temperature does not exceed a predetermined value for efficient operation. In addition, the voltage of each cell may be measured to provide an accurate determination of the state of charge, to facilitate energy balancing between cells, and/or to ensure that the voltage does not exceed a predetermined value.
Certain battery monitoring systems include a battery management unit configured to receive electrical power from the battery array, and to transfer the electrical power to an electrical distribution system. The battery management unit may also be configured to receive signals from cell measurement electronics which monitor various parameters of the battery cells within the array. For example, a printed circuit board (PCB) may be associated with each battery cell, or group of battery cells, within the array. In such configurations, the PCB is electrically connected to each terminal of the battery cell to measure output voltage. To account for variations in cell dimension and/or vehicle movement, spring connectors, wire harnesses or flex circuit assemblies may be employed to establish the electrical connection between each terminal of the battery cell and the PCB. For example, a spring connector, wire link or flex circuit may be welded or soldered to the PCB, and secured to the terminal by a fastener (e.g., screw, washer, etc.). Unfortunately, movement of the vehicle may cause such connections to wear over time, thereby degrading the electrical power signal to the PCB, and interfering with battery cell monitoring operations.
In such arrangements, each PCB is configured to transmit the measured battery cell parameters to the battery management unit. In certain configuration, electrical cables may extend between the PCBs and the battery management unit, forming a bus (e.g., CAN bus). Unfortunately, the electrical cables increase the weight and production costs of the battery monitoring system. In addition, the cables may wear over time, thereby degrading the signals from the PCBs to the battery management unit. As a result, the overall efficiency of the battery array may be reduced.